S = input()
N = len(S)
ans = 0
def isPalindrome(p):
	s,t,c = 0,len(p) - 1,0
	while s < t and p[s] == p[t]:
		s,t,c= s + 1,t - 1,c + 2
	if s == t and p[s] == p[t]:
		c += 1
	return c == len(p)
for i in range(N):
	for j in range(i,N):
		if len(S[i:j + 1]) < N and isPalindrome(S[i:j + 1]):
			ans = max(ans,len(S[i:j + 1]))
print (ans)